Objective 2.0

Junos OS Fundamentals

JNCIA-JUNOS Practice Questions

Use this page to practise Junos OS Fundamentals questions for this certification. Focus on how the exam tests junos os fundamentals in scenario format — understanding the why behind each answer builds more durable knowledge than memorising options.

Full Practice Test →All Objectives

What this objective tests

JNCIA-JUNOS Junos OS Fundamentals — Key Topics

Junos OS Fundamentals questions on this certification test your ability to deploy and manage junos os fundamentals concepts in scenario-based situations.

Core Junos OS Fundamentals concepts and how they apply in real-world cloud scenarios.
How to deploy junos os fundamentals correctly and verify the outcome.
Troubleshooting junos os fundamentals issues by interpreting error output and system state.
Cloud best practices and Junos OS Fundamentals design trade-offs tested by this certification.

Common exam traps

Where candidates lose marks on Junos OS Fundamentals

⚠Selecting the most expensive service when a simpler managed option meets the requirement.
⚠Forgetting that cloud resources must be explicitly secured — defaults are rarely secure.
⚠Choosing a global service fix when the issue is region-specific.
⚠Overlooking cost implications of cross-region data transfer in architecture questions.

JNCIA-JUNOS Junos OS Fundamentals — Practice Questions

30 questions from this objective

Question 2mediummultiple choice

Junos OS Fundamentals

JNCIA-JUNOS Junos OS Fundamentals — Key Topics

Where candidates lose marks on Junos OS Fundamentals

JNCIA-JUNOS Junos OS Fundamentals — Practice Questions

A network engineer is configuring a new Juniper device and needs to ensure that the configuration is saved persistently across reboots. Which command should be used?

An administrator needs to quickly revert all uncommitted configuration changes and return the device to the last committed configuration. Which command accomplishes this?

A Juniper device is experiencing high CPU utilization due to a routing protocol process. The engineer suspects a specific BGP peer is causing the issue. Which operational command can be used to collect diagnostic information about the routing protocol processes?

A junior engineer is troubleshooting connectivity issues and wants to trace the path packets take to a remote destination. Which Junos command should be used?

An engineer needs to view the current active configuration on a Juniper device. Which command will display the configuration that is currently running?

A network administrator is configuring a new interface and wants to ensure that the interface is enabled and can pass traffic. Which configuration element is required?

During a maintenance window, an engineer needs to apply a series of configuration changes that are stored in a text file. Which command sequence should be used to load and apply the changes from the file?

An engineer notices that a Juniper device is not saving configuration changes across reboots. What is the most likely cause?

Which TWO statements are true about the Junos OS candidate configuration model? (Choose two.)

Which THREE commands are valid Junos operational mode commands for monitoring network diagnostics? (Choose three.)

Which TWO statements correctly describe the function of the 'commit' command in Junos OS? (Choose two.)

Based on the exhibit, what is the most likely reason for the ping failure?

Exhibit

Based on the exhibit, what is the most likely impact on the router?

Exhibit

A network engineer notices that a Junos device is not forwarding traffic for a specific subnet. The routing table shows the route for that subnet, but traffic is still not being forwarded. Which command should the engineer use to verify whether the firewall filter is dropping the traffic?

Which THREE of the following statements are true regarding Junos OS commit operations?

Refer to the exhibit. An engineer wants to verify that static routes for 10.0.1.0/24 and 10.0.2.0/24 are present in the routing table. Based on the output, which statement is true?

Exhibit

A network engineer needs to check the operational status of all interfaces on a Juniper device. Which command provides a summary of interface status including link state, protocol state, and error counters?

Which THREE statements are true about commit operations in Junos OS?

Refer to the exhibit. How many next hops are configured for the 192.168.1.0/24 route?

Exhibit

Order the steps to configure a user account with a password in Junos.

Match each Junos file system directory to its content.

Which Junos CLI mode allows a user to view the configuration and execute operational commands, but not make configuration changes?

A network administrator makes several changes to the configuration but decides to discard all uncommitted changes and start fresh. Which command should be used to revert the candidate configuration back to the current active configuration?

A Juniper device fails to boot and stops at the 'loader>' prompt. What is the most likely cause of this issue?

Which command displays the current hostname of a Junos device?

An administrator needs to grant a user read-only access to the device via SSH. Which configuration should be applied?

A technician notices that the /var partition on a Junos device is 95% full. Which action will immediately free up disk space without affecting device operation?

All JNCIA-JUNOS Objectives

Junos OS Fundamentals

JNCIA-JUNOS Junos OS Fundamentals — Key Topics

Where candidates lose marks on Junos OS Fundamentals

JNCIA-JUNOS Junos OS Fundamentals — Practice Questions

A network engineer is configuring a new Juniper device and needs to ensure that the configuration is saved persistently across reboots. Which command should be used?

An administrator needs to quickly revert all uncommitted configuration changes and return the device to the last committed configuration. Which command accomplishes this?

A Juniper device is experiencing high CPU utilization due to a routing protocol process. The engineer suspects a specific BGP peer is causing the issue. Which operational command can be used to collect diagnostic information about the routing protocol processes?

A junior engineer is troubleshooting connectivity issues and wants to trace the path packets take to a remote destination. Which Junos command should be used?

An engineer needs to view the current active configuration on a Juniper device. Which command will display the configuration that is currently running?

A network administrator is configuring a new interface and wants to ensure that the interface is enabled and can pass traffic. Which configuration element is required?

During a maintenance window, an engineer needs to apply a series of configuration changes that are stored in a text file. Which command sequence should be used to load and apply the changes from the file?

An engineer notices that a Juniper device is not saving configuration changes across reboots. What is the most likely cause?

Which TWO statements are true about the Junos OS candidate configuration model? (Choose two.)

Which THREE commands are valid Junos operational mode commands for monitoring network diagnostics? (Choose three.)

Which TWO statements correctly describe the function of the 'commit' command in Junos OS? (Choose two.)

Based on the exhibit, what is the most likely reason for the ping failure?

Exhibit

Based on the exhibit, what is the most likely impact on the router?

Exhibit

A network engineer notices that a Junos device is not forwarding traffic for a specific subnet. The routing table shows the route for that subnet, but traffic is still not being forwarded. Which command should the engineer use to verify whether the firewall filter is dropping the traffic?

Which THREE of the following statements are true regarding Junos OS commit operations?

Refer to the exhibit. An engineer wants to verify that static routes for 10.0.1.0/24 and 10.0.2.0/24 are present in the routing table. Based on the output, which statement is true?

Exhibit

A network engineer needs to check the operational status of all interfaces on a Juniper device. Which command provides a summary of interface status including link state, protocol state, and error counters?

Which THREE statements are true about commit operations in Junos OS?

Refer to the exhibit. How many next hops are configured for the 192.168.1.0/24 route?

Exhibit

Order the steps to configure a user account with a password in Junos.

Match each Junos file system directory to its content.

Which Junos CLI mode allows a user to view the configuration and execute operational commands, but not make configuration changes?

A network administrator makes several changes to the configuration but decides to discard all uncommitted changes and start fresh. Which command should be used to revert the candidate configuration back to the current active configuration?

A Juniper device fails to boot and stops at the 'loader>' prompt. What is the most likely cause of this issue?

Which command displays the current hostname of a Junos device?

An administrator needs to grant a user read-only access to the device via SSH. Which configuration should be applied?

A technician notices that the /var partition on a Junos device is 95% full. Which action will immediately free up disk space without affecting device operation?

All JNCIA-JUNOS Objectives